Thanks for the welcome Ken, I'm well aware of the potential for low voltage electronic mayhem especially as it improved a lot once I had the alternator rebuilt due to a dead diode in the pack and subsequently I had many of the crimp connectors in the battery circuit soldered to get around a small voltage drop on each one.
One thing many may not be aware of is the alternator on the diesel contains a freewheeling clutch which I'm told by the auto electrician should be a service item. Certainly mine was stuffed at around 120-130km's

 

Hi Sheppy,

Thanks for your well laid out explanations and follow-up in this matter. Thanks also for reminder of freewheeling clutch on alternator fitted to TTD. More to add . . . Yes; they are different to those on the petrol engined cars; but also . . . I had previously noted differing part numbers for pre and post 2006 TTD alternators, so now I wonder why. Was this clutch changed? Was some other part or feature of the 2.7L TTD alternator upgraded or changed?

Amid so many other 2.7L TTD engine component and systems upgrades for 2006, I have not been able to solve this . . . indeed some listings do not include both numbers. Suggest ALL owners of 2.7L TTD vehicles double check this before ordering any replacement.

One day, we may discover a complete listing of all these quirks, but I suspect the final answer for 2007/8 S-Types and 2.7L TTD in particular, is that Jaguar Cars in this final production period, brought together all they could muster to boost lagging sales . . . and this appears to include pending engineering upgrades (pre XF) as well as fitting all remaining stocks of luxury S-Type options.

Regards,

Ken

 

Hi Ken,
one interesting thing told to me by the auto electrician is the diode packs on these alternators are too cheap and often fail particularly in Fords so maybe the 2006 onwards had a better pack. He fitted a better designed one to mine, and looking at the waveform of the old one I'd expect it was only one out of the six diodes that had gone so only slightly down in output. There was however a slight wavering on the black background of the touchscreen.

 

Yep; that's a logical possibility. I can't see separate part numbers here for diode packs, but you may well be right. If so, this could be the reason for different o/a part numbers post MY06.

Let me also confirm what Cameron has said about interchangeability of Ford and LR subsystems when looking at parts replacements for the 2.7L TTD V6 engine. We could also add the Euro cousins, but they would be unlikely to offer any cost or availability advantages like Ford Territory or LandRover Discovery.

I am constantly discovering that eBay suppliers of new parts - from filters to serpentine belts - show up identical part numbers from Jag, LR and Ford. Used this knowledge to purchase 4x oil filter elements @ $9 each - that's almost exactly what 1x Jaguar filter costs from Ryco. A serpentine belt sells for less than $40 . . . and that's delivered to your door post free! Having just bought a standard A section 108 belt for my ride-on lawn mower @ $70, I know great value when I see it.

Naturally, I would advise caution when looking at sensors, injectors etc and more so from MY06 onwards, by which time, Jaguar's in house series of re-engineered developments of the TTD V6 engine were well under way. Your example of the "smart" alternator and initially inferior (but then perhaps upgraded) diode packs, is a fitting reminder.

Sheppy, please keep us updated with your summary of how your car is now performing.
Best wishes,
Ken